1. Field of the Invention
The present invention relates to novel sulfide, polysulfide, selenide and polyselenide compositions useful as solid electrolytes. More particularly, this invention relates to the sulfide, polysulfide, selenide and polyselenide compositions useful as ionic conducting solid electrolytes and electrical energy storage devices utilizing such electrolytes.
2. Description of Art:
Significant research is presently being conducted to develop new types of energy storage devices. One area of research receiving considerable emphasis is a search for better solid cation conductors which can be utilized in energy storage systems. Solid electrolytes may provide distinct advantages as compared with liquid electrolytes in the manufacturing of solid state high-energy storage devices. For example, the solid electrolyte eliminates many of the problems found in manufacturing energy storage devices with corrosive electrolytes. Further, the ionic conducting solid electrolytes can replace current molten salt electrolytes and be utilized at room temperatures.
The article Ionic Conductivity of Solid Liquid LiAlCl.sub.4 by W. Weppner et al. discloses the electrical conductivity of lithium chloroaluminate in a temperature range between room temperature and 180.degree. C. The article Negative Oxidation States of the Chalcogens in Molten Salts. 1. Raman Spectroscoptic Studies on Aluminum Chlorosulfides Formed in Chloride and Chloroaluminate Melts and Some Related Solid and Dissolved Compounds by Rolf W. Berg et al. discloses Raman spectroscopic measurements on series of LiCl-CsCl and CsCl-AlCl.sub.3 melts. Also disclosed therein is a novel sulfur-containing compound of the formula CsAlSCl.sub.2. However, the use of these compounds as electrolytes was not discussed in this article. Finally, the article Novel Materials for Advanced Batteries by B. C. H. Steele disclose at page 371 non-crystalline lithium ion conductors of the formula Li.sub.2 S-P.sub.2 S.sub.5 -LiI and polymeric ethylene oxides and propylene oxides incorporating lithium salts.